Pressure-fluid tool.



G. H. GILMAN.

PRESSURE FLUID-TOOL.

APPLICATION FILED JAN- 4. HM].

1,2 3 6, 70 4 Patented Aug. 14, 1917.

GEORGE H. GILMAN, OF CLAREMONT, NEW HAMPSHIRE, ASSIGNOR TO SULLIVANcnusnrrs.

1,236,704. Original application filed April 22, 1908,

' Specification of Letters Patent.

MACHINERY COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OFPRESSURE-FLUID TOOL.

Patented Aug. M, rem.

Serial No.'428,618. Divided and this application filed January 4,

1917. Serial No. 10,631.

To all whom it may concern:

Be it known that I, GEORGE H. Gunman, a citizen of the United States,and a resident of Olaremont, county of Sullivan, and State tion, .likecharacters on the. drawings representing like parts.

My invention relates to pressure flu1d tools adapted to be operated bycompressed air, or other elastic pressure fiuid,"be1ng -moreparticularly concerned with the provision of simplified and etlicientvalve controlling means therefor. This application is a division of myprior pending application, Serial No. 428,618,1il5d April 22, 1908.

My invention will be best understood by reference to the followingdescription, when taken in connection with the accompanying illustrationof one specific embodiment thereof, while its scope will be moreparticularly pointed out in the appended claims.

In the drawings:

, Figure 1 is a longitudinal, central section, taken through a pneumatichammer embodying one form of my invention; and

Fig. 2 is a similar sectional view taken in a plane at right angles tothe plane of the section shown in Fig. 1.

Referring to the drawings, and to the embodiment of my inventionillustrated therein, there is provided a cylinder 1, the rear or upper(Fig. 1) end of which has threaded engagement with a hollow casing 2,the latter having a closed end and acting as a housing for the rear endof the cylinder, and a valve block-'3. The cylinder is prevented fromaccidental unscrewing by a split vclamping collar 4. A portion of ahandlepiece 5, or other member by which the tool is supported, is shown,but it will be understood that the particular construction of handleforms no material part of this invention, and that the same may be usedwith various handles or other supports wellknown in the art.

The upper or rear end of the cylinder is closed by a plate 6,betweenwhich and the casing 2 a valve block 3 is -secured. The cylinder,valve block and plate, are maintained in the alinement required for theregistration of their connecting passages by means of a dowelpin 8.

The head of the casing is recessed as at 9 to provide a constantpressure supply chamber, to which, when the tool is in use, compressedair or other pressure fluid isvconstantly supplied through an air inlet10.

The valve block is of generally cylindrical shape, and has an interiorlyformed valve chamber axially alined with the cylinder. The valve 11 isprovided with an enlarged head 12 and a contracted head 13, the twobeingseparated by an annular groove 14: and the enlarged head being alsoprovided with a second annular groove 15. The valve chamber has anopening 16 in its rearmost end, communicating with the pressure fluidchamber 9, so that the end of the smaller head 13 is constantly exposedto pressure fluid and forced forward, The valve is shown hollowed orcored out for the sake of lightness.

The enlarged forward end of the valve works in an intermittent pressurechamber 17 communicating with an intermittent pressure passage 18through a grooved passage 19 formed in the upper face of the plate 6.The rear contracted end of the valve chamber is provided with twoannular grooves'20 and 21, each of which is connected with the rear endof the cylinder by one or mqre longitudinal passages 22 (Fig. 2).- Inthe forward position of the valve (Fig. 2), the groove 20 is uncoveredby the end edge of the smaller valve head, and pressure fluid isadmitted directly to the longitudinal passage 22, and the rear end ofthe cylinder. In the rearward position of the valve (Fig. 1), the groove21 is uncovered by the inner edge of the'smaller head 13, and placed incommunication through the annular groove 14 with the upper end of theenlarged portion of the valve chamber,.which latter is in constantcommunication with an annular exhaust chamber 23, through one or moreradial exhaust ports 24.

In the forward position of the valve (Fig. 2) J, corresponding to theforward movement of 'the piston, the forward end of the cylinder isopened to the exhaust through a return passage-25, which latter connectswith a lateral pfi't26 opening into the larger end of the valvechambefirt-such a point as to be uncovered by the larger head 11 andplaced in communication with the exhaust port 24. through the annularvalve groove 14.

During the forward movement of the piston, the valve is held in theposition shown in Fig. 2 by the pressure acting against the constantpressure area at the rear end of the valve until the piston nears theend of its stroke and the delivery of its blow upon the shank of a tool.27 the latter being held within a usual sleeve or bushing 28.

Near the close of the forward movement of the piston, the controllingvalve is reversed by the admission. of pressure fluid to the forward endof the enlarged portion 17 of the valve chamber, which fluid, actingagainst the larger pressure area of the valve at that end, acts toreverse the valve against the constant pressure upon the smallerpressure area at the rear end of the smaller head 13.

Pressure fluid is admitted against the enlarged forward end 12 of thevalve, and to the lower end of the chamber 17 through the intermittentpressure passage 18 and groove 19 hereinbefore referred to, said passageopening into the cylinder through a port 29,

and also through a second and more advanced port 30.

The intermittent passage is placed in communication with a constantpressure passage 31, which latter opens into the cylinder through a port32, by means of the circumferential groove 33 formed in the piston.

- When the circumferential groove uncovers the ports 32 and. 29,pressure fluid is admitted to the lower end of the valve chamber toraise the valve. The constant pressure passage 31 is connected at itsrear end in the valve block by a transverse groove or' passage 34, whichopens communication between the pressure chamber 9 and a longistantcommunication with the pressure fluid supply.

The exhaust space or chamber'23 hereinbefore referred to is annular, andis interposed between the valve block and the housing or casing 2, the.latter being perforated at one or more points, such as 36 and 37, so asto permit free exhaust of pressure fluid to the atmosphere through theport or ports 24.

The piston has a reduced portion 38, having sliding fit within the,contracted walls 39 of the cylinder, the effective area against whichthe pressure acts in returning the piston being that provided by theshoulder formed between the contracted port-ion and the main bodyportion of the piston.

When the return piston movement has proceeded far enough to withdraw thereduced portion 38 from the contracted cylinder walls 39, the forwardend of the cylinder is placed in communication with a tool space 40, thelatter being in free communication with the atmosphere through anexhaust of the valve again. from the position shown in Fig. 1 to thatshown in Fig. 2, this, in turn, admitting pressure fluid to the rear endof the cylinder through the circumferential chamber groove 20 and thepassage 22, as previously described.

During the subsequent forward movement of the piston, after the reducedpiston portion 38 enters the contracted cylinder walls 39, pressurefluid continues to be exhausted from the forward end of the piston priorto the reversal of the valve through the return passage 25 and port 26,which latter, on the forward movement of the valve, is uncovered by thelarger valve head 12, and thereby opened to the foremost end of thevalve chamber. The latter is at all times open to the exhaust throughthe lateral exhaust port 24 formed in the Valve block (Fig. 2), andconnecting the end 17 of the valve chamber with the annular exhaustchamber 23.

While I have shown and described in detail one specific embodiment of myinvention, it is to be understood that the same is not limit-ed to thedetails shown or the construction or relative arrangement of the partsdisclosed, but that extensive modifications may be made therefromwithout departing from the spirit of my invention.

Having thus described one specific embodiment of my invention, what Iclaim-and desire to secure by Letters Patent is 1. A pressure fluid toolhaving a cylinder,

a piston, an imperforate diflerential valve having two heads ofdifferent diameter and two annular grooves, a valve block provided witha valve chamber having an enlarged portion and a contracted portion inwhich the larger and smaller heads are respectively located; a pair ofports in the contracted portion of the valve chamber communicating eachwith one end of the cylinder, the

valve in one position acting to open one of said ports to the livepressure and to cover the other port, andin the other position to coverthe one port and to open the other port to the exhaust by way of onevalve groove,

' andza port connected with the other end-of the cylinder opening intothe enlarged portion' of the valve chamber, the valve in the lastmentioned position establishing com-. Imunication between the-lastmentioned port and the motive fluid supply by way of the other valvegroove.

1 block, a pair of ports formedin the con-v the cylinder, the rear endof the valve being 2. A pressure fluid tool having a cylinder a piston,a valve provided with two heads 0 different diameter, the larger ofwhich is provided with an annular groove, a valve block and its valvechamber in which said valve is adapted to work, the smaller head of saidvalve and the contracted portion of said chamber being located in therear of said tracted portion of the said valve chamber and connectedeach 'with the rear end of constantly opened to pressure fluid, anexhaust passage in constant communication with the rear end of theenlarged portion of said valve chamber, and a passage connected with.the forward end' of the cylinder, said,

valve acting in one position to connect one of said ports with the rearend of the contracted portion of .said valve chamber, and, at the sametime, to connect the said passage leading to the forward end of thecylinder with the rear end of the enlarged valve chamber-portibn', andin its other position to connect the remaining port with the rear of theenlarged valve chamber-portion, and the pressure supply with the passageleading to the forward end of the cylinder by way of said annular groovein the larger head of said valve.

3. A pressure fluid tool having a cylinder, a piston, a differentialvalve of two diameters, having its smaller area constantly exposed topressure fluid, a port communieating with the rear end of the cylinderand adapted to be uncovered by the smaller end of the valve when in oneposition, an annular valve groove between the smaller and largerdiameters of the valve and in constant communication with the exhaust, aport conthe other valve groove.

nected' with the pressure fluid and opening into theenlarged portion ofthe valve chamher, an annular groove insaid valve adapted to registerwith said port ih'one position of the'valve', and a passage leading, tothe forward end of the cvlinder, said passage in one position of thevalve being placed in communication with said live pressure port, and inanother position thereof in communication with the said exhaust passage.

4. A pressure fluid tool having a cylinder, a piston, a valve having twoheads of difi'ercm diameter, a, valve block having a valve chamber openat its rear end to the pressure fluid, said'valve having its headofsmaller diameter exposed tov the said pressure fluid, an annular oovein' said valve chamber connecting with the rear end of the cylinder andadapted to be placed in communication with the open end of-said valveblock by the forward movement of the valve, an annular groove in thelarger head of the valve, a live pressure port'and a cylinder portcommunicating with the forward end of the cylinder, said valve in itsrearward position acting to place said pressure port and cylinder portin communication by way ofsaid annular groove-in the larger head of saidvalve.

' 5. A pressure fluid tool having a cylinder, a piston, a differentialvalve having two heads of difl'erent'diameter and two annular grooves, avalve block provided with a'valve chamber having an enlarged portioncommunicating with one end of said cylinder and a reduced portioncommunicating with the motive fluid supply,-' the larger head of theother port, and in the other position to cover the first port and openthe other port to the exhaust by way of one valve groove and to open theother end of the cylinderto the motive fluid supply solely by way on 6.A pressure fiuid tool having a-cylinder, a piston, a differential valvehaving two heads of difi'erent diameter. an annular groove intermediatesaid heads and an annular groove in the larger head of said valve, avalve block provided with a valve chamber having an enlarged portioncommunicating with one end of said cylinder and a reduced portioncommunicating with the motive fluid supply, the larger head of'saidvalve working in the enlarged portion of said valve chamber and thesmaller head working in the'reduced portionof said valve chamber, a

said valve workin in the enlarged portion 10 valve when ,in the otherposition acting to open such other end of the cylinder to the motivefluid supply by way of the annular groove in the larger head of saidvalve and to open the other chamber groove to the ex haust by Way of theintermediate valve 15 groove. a I

In testimony whereof I have signed my name to this specification.

GEORGE H. GILMAN.

